This invention relates to an apparatus for preventing freezing of interior hot and/or cold water pipes and fixtures during cold weather.
It is well known that one way of preventing a water pipe from freezing during cold weather is to manually open an outlet valve in the pipe and allow water to slowly flow (trickle) therefrom. However, this technique requires the input of a human being who may or may not be present when flow should be instituted or terminated.
A number of devices have been proposed over the years for preventing water pipes of buildings from freezing in cold weather by automatically causing water to drain or trickle therefrom in response to a drop in temperature below the freezing point.
U.S. Pat. No. 299,392 discloses one such device. Metal rods C and F that expand and contract with heat and cold open and close a valve B connected to a waste water line D. The waste water line D is connected to a service water pipe A. This device relies upon outside temperatures to actuate the bleed valve since rod C is illustrated as being located outside the building.
U.S. Pat. No. 1,226,696 discloses a device which cuts off the supply of water to the supply pipe of a house and drains it when the temperature falls below freezing.
U.S. Pat. No. 4,286,613 discloses a particular type of temperature sensitive valve for bleeding water from a plumbing system when the temperature drops below freezing.
U.S. Pat. Nos. 4,469,118 and 4,657,038 disclose apparatus for slowing bleeding water from an outdoor water line when the outdoor temperature drops below freezing.
Many of these devices, when in the bleeding or trickling mode, prevent normal water usage of the building plumbing. Furthermore, all of these devices respond to ambient inside or outside air temperature which does not normally represent the temperature of the water in the water lines.
The objects of the present invention are: (1) to provide an automatic water trickling system to prevent freezing of interior water lines which does not interfere with the normal usage of water from those lines; (2) to provide such a system that is closely responsive to water temperatures in such water lines at freeze prone remote locations; and (3) to prevent water wastage. These and other objects will become apparent from the description of the preferred embodiments of this invention described below.